Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!batcomputer!cornell!uw-beaver!mit-eddie!media-lab.media.mit.edu!masaru From: masaru@media-lab.media.mit.edu.MEDIA.MIT.EDU (Masaru Sugai) Newsgroups: comp.sys.amiga.hardware Subject: Re: A3090 tape driver ??(Re: BTN 2.0 Tape handler) (a bit long...) Summary: quick measurements here ! Keywords: A3070, A3000, QIC, tape, Message-ID: <5704@media-lab.media.mit.edu.MEDIA.MIT.EDU> Date: 23 Apr 91 08:27:56 GMT References: <1991Apr13.014520.13657@sugar.hackercorp.com> <61897@masscomp.westford.ccur.com> <5692@media-lab.media.mit.edu.MEDIA.MIT.EDU> <41542@cup.portal.com> Reply-To: masaru@media-lab.media.mit.edu (Masaru Sugai) Organization: MIT Media Lab, Cambridge MA Lines: 87 First of all, I appologize for my misunderstanding. I got an e-mail from Bob (author of BTNtape), and he suggested me to use BS-512 as most of tape drives have a fixed length buffer size of such, and NB as many as possible. Here go my quick results of TAR + BTN2.0 performance. Configuration A3000/16 w/ 2MB CHIP, 4MB FAST built-in SCSI A3070 150MB tape drive (C=) mountlist Startup PARAMETER BS-512, OV-1, UN-4 productivity w/ 4 color Full dump ---------------------------------------------------------------------------- (1) Dumping 27MB of WORK: partition (NB-128) 12:10 cd work: tar cvf tape: . (2) Listing of archived tape (1) (NB-128) 7:50 tar tvf tape: NOTE: I have no disk space to restore them :( --------------------------------------------------------------------------- NB variation -------------------------------------------------------------------------- Dumping and restoring 3.9 MB files tar cvf tape: . tar xvf tape: (5) NB-128 2:18 0:50 (6) NB-256 1:32 not measured (7) NB-1024 1:00 not measured (8) NB-2048 1:00 0:47 -------------------------------------------------------------------------- Test conditions are really ad hoc, but it should delineate real characteristic of NB factor over total performance. The break even point seems to lay between 256 and 1024, but I haven't checked in-between setting as of yet. [BTW, I found several discrenpancies in tape.doc documentation. It might be peculiar to 2.0, I guess. - "type > tape: tape.doc" works fine, but WB "can't open tape:" for "type tape:". Strange to say, WB prefers "more tape:" - "assign tape: removed" should be "assign tape: dismount" in WB2.0. There is a dreadful notice in AmigaDOS reference though. ] According to the '3070 tape drive installation guide', data transfer rate of A3070 is 112.5KB/sec. (8) gives approximately 65(81)KB/sec, about 58(72)% of maximum transfer rate. I have no idea what to interpret these numbers, but an article "TAPE BACKUPS" in Nov 1990 issue of MacWorld carries a benchmark tests, and typical 150MB stand at over 75KB/sec for file-by-file backup. With this price range, A3070 could be a better buy if C= would support tape driver for non-UNIX Amigas :) I'm still wondering how much I can actually store on a single cartrige. Any suggestions and comparisons (especially tape drives in other platform) are very welcome. As for data exchange with UNIX, I was successful to read out archived files from SUN4 this morning. We have HPs around at the lab, but they only gave me fault light :( In essence, BTN2.0+TAR works for A3000+A3070 at reasonable transfer rate as long as NB is set to an appropriate number, and tapemon is a good accessory just in case. -- Masaru Sugai PS FYI: This is the initial message from 'tapemon'. Thanks Bob ! *** BTN-Tape Handler & Monitor *** ) Copyright 1990,1991 Robert Rethemeyer TAPE: Proc 7C7BFF0 DevNode 7C2DA04 scsi.device Unit-4 LU-0 Drive: CALIPER CP150 A Sequential Access Last sense= FILEMARK, other=00,01 Use ^C to terminate TapeMon -BTNTAPE V2.0 RAR-Mar 29 1991 TapeMon terminated -- -- Masaru Sugai:Use disclaimer. CIS 72050,2141:NeXT + A3000 = money-eater NEC Corporation:sugai@ccs.mt.nec.co.jp DORMANT:hardwired logic,machine language MIT R.Affiliate:masaru@media-lab.media.mit.edu: "Silicon on Sapphire" by CLASH